This invention relates to improved ball joint links that are light in weight and inexpensive to manufacture, and to methods for forming such links.
Molding techniques in the past have been used in the fabrication of various ball joint components. For example, Duncan U.S. Pat. No. 3,941,495 teaches a method for forming a ball around a stud to form a ball stud.
Sinclair U.S. Pat. No. 5,277,860 discloses an all-plastic rod end in which opposed raceways are mated to form a socket around a ball. The raceways are then overmolded to complete fabrication of the rod end.
Memory U.S. Pat. No. 3,591,669 discloses a plastic universal bearing which is molded in place in a link. In this case, the plastic that forms the socket of the ball joint is integral with the plastic that forms the center section of the link.
Hellon U.S. Patent Application Ser. No. 08/253,688, filed Jun. 3, 1994 and assigned to the assignee of the present invention, discloses an insert molded ball joint as shown in attached FIG. 8. The ball joint of Hellon includes a housing 100 which is insert molded around three separate parts: a tubular center section 102 of a ball joint link, a ball 104 of a ball stud 106, and a cap 108. A high-strength, fiber-reinforced plastic is used for the housing 100, and the same high-strength material that forms the housing 100 both secures the housing 100 to the center section 102 and forms the bearing surface for the ball 104. In this way, high pull out forces are required to dislodge the ball stud 106 from the housing 100.
The present invention differs significantly from the prior art of FIG. 8, particularly with respect to the manner in which the ball stud is retained in the ball joint, the manner in which the ball joint socket is formed, and the manner in which the ball joint is molded.